Bleeding tool for hydraulic brake cylinder

ABSTRACT

A bleeding tool for loosening as well as removing gases from an external bleeding member of a hydraulic brake cylinder. The tool contains a generally hollow interior defining a passageway for fluid therethrough. The front end of the tool is formed of a socket member for loosening the bleeding member and enabling the fluid to pass from the brake cylinder through the passageway. The rear end of the tool contains an interconnection device for removing fluid from the passageway. A resilient member is positioned in the tool interior adjacent a front end thereof and has a bore surface therethrough defining a continuation of the tool passageway. A tubular member interconnects the bore surface of the resilient member with the tool passageway. A spring positions the resilient member adjacent the bleeding member for enabling the resilient member to provide a seal between the tool and the bleeding member, thus enabling fluid to pass directly from the bleeding member to the passageway without leakage.

United States Patent [191 Truelove, Sr.

[4 1 May 7,1974

[ BLEEDING TOOL FOR HYDRAULIC BRAKE CYLINDER [76] Inventor: Edward L. Truelove, Sr., 14836 Callahan St., Panorama City, Calif. 91402 221 Filed: Jan.1l, 1973 211 Appl. No.: 322,667

[52] U.S. Cl 251/148, 81/121,141/98,

. 188/352 [51] Int. Cl. Fl6k 51/00 [58] Field of Search 251/148; 81/121; 'l84/1.5; 188/352; 141/98 7/1972 Truelove, Sr. 141/98 Primary ExaminerHouston S. Bell, Jr. Attorney, Agent, or FirmNilsson, Robbins & Berliner [5 7] ABSTRACT A bleeding tool for loosening as well as removing gases from an external bleeding member of a hydraulic brake cylinder. The tool contains a generally hollow interior defining a passageway for fluid therethrough. The front end of the tool is formed of a socket member for loosening the bleeding member and enabling the fluid to pass from the brake cylinder through the passageway. The rear end of the tool contains an interconnection device for removing fluid from the passageway. A resilient member is positioned in the tool interior adjacent a front end thereof and has a bore surface therethrough defining a continuation of the tool passageway. A tubular member interconnects the bore surface of the resilient member with the tool passageway. A spring positions the resilient member adjacent the bleeding member for enabling the resilient member to provide a seal between the tool and the bleeding member, thus enabling fluid to pass directly from the bleeding member to the passageway without leakage.

7 Claims, 4 Drawing Figures BLEEDING TOOL FOR HYDRAULIC BRAKE CYLINDER DESCRIPTION OF THE PRIOR ART 1. Field of the invention The invention relates to bleeding tools for hydraulic brake cylinders, particularly with respect to a bleeding tool having a spring-biased sealing arrangement for preventing leakage of the fluid from the brake cylinder.

2. Description of the prior art The best known prior art includes US. Pat. Nos. 3,301,282 and 3,677,513.

To prevent leakage of brake fluid from a hydraulic brake cylinder when bleeding the cylinder, specialized tools have been designed which combine the function of first loosening the bleed screw nut while simultaneously providing a passageway for the fluid which is to be discharged. One form of prior art combined loosening and bleeding tools utilizes a tubular member formed within the tool with the front end of the tubular member bent inwardly and defining a smaller diameter than the diameter of an outer rim formed adjacent the opening in the bleed screw. The front end of the tubular member must be pushed over the. tip of the bleed screw. Continued usage of the tool results in the front end-of the tubular member fraying or breaking and thus not providing a seal between the tool and the bleed screw.

In a similar type arrangement, an interference fit is formed between a plastic transition member formed in the tool, and the front end of the bleed screw. Such an interference fit uses a transition member which is normally made of neoprene or polyethylene which is snapped into place and has resulted in breakage and failure of the seal between the tool and the bleed screw, particularly when used for prolonged periods of time.

In order to overcome the attendant disadvantages of prior art bleeding tools which can be used to loosen the bleed screw, as well as form a passageway forremoving fluid from a hydraulic brake cylinder, the present invention provides a positive sea between the tool and the bleed screw. The seal is made of a material which maintains a good seal even after continued usage. In addition, interconnection is provided'between the tool and an external reservoir for draining the fluid from the brake cylinder into the reservoir. The tool contains means for rapidly loosening a bleed screw and enabling the fluid to be drained from the brake cylinder.

SUMMARY OF THE INVENTION A bleeding tool for loosening as well as forming a passageway for removing gases from the bleeding member of a hydraulic brake cylinder. The tool has a generally hollow interior defining a passageway for fluid therethrough. The front end of the tool is made so that it can be used for loosening the bleeding member of the brake cylinder enabling fluid to pass from the cylinder through the passageway of the tool. The rear end of the tool can be connected to a fluid removal device for removing fluid from the passageway. A resilient member is positioned in the tool hollow interior, adjacent the front end of the tool. A bore surface in the resilient member defines a continuation of the tool passageway. A tubular member interconnects the bore surface of the resilient member with the tool passageway. A

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a hydraulic cylinder and a tool made in accordance with the invention for bleeding fluid from the cylinder;

FIG. 2 is a cross-sectional view of a portion of the brake cylinder and the tool illustrating the initial positioning of the tool adjacent the brake cylinder;

FIG. 3 is a sectional view of the brake cylinder and tool of FIG. 2 illustrating the position of the tool as fluid is drained from the cylinder; and

FIG. 4 is a cross-sectional view illustrating the interconnection between the tool and the end of the passageway in the toolv for removing fluid from thetool.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1, there is shown an L-shaped bleeding tool 12 made in accordance with principles of the invention. The tool 12 is typically used to bleed fluid from a hydraulic brake cylinder 14 into a reservoir 16 which is connected to the tool 12 by means of an adaptor member 18. Typically, such an operation is required when air or other gases are present in the brake fluid path of a vehicle, although the tool has other uses as well. The hydraulic brake cylinder 14 is of conventional design and found on most automobiles with brake fluid being delivered to the cylinder through a line 22 which, in turn, causes plungers 24 and 26 to move outwardly. A bleed screw 28 is provided for bleeding thefluid from the brake cylinder 14 as well as the connecting lines.

Whenthe fluid is to be bled, the bleed screw 28 is loosened and fluid flows therefrom as is conventional. The present tool 12 combines the function of both loosening the bleed screw 28 and providing a sealed passageway for passage of the fluid from the brake cylinder 14 into the reservoir 16.

Referring now to FIG. 2, the bleed screw 28 is shown in greater detail in cross-sectional view. The bleed screw 28 is threadably connected to a bore 32 of the brake cylinder and is in a closed position by the action of a cylinder seat 34 in the bore, as well as a screw seat 36 at the front end of the bleed screw which blocks fluid from entering the bleed screw from the brake cylinder passageway 38. The bleed screw 28 contains a conventional main passageway 40 which extends along the axis of the bleed screw and is connected by means of a right angle passageway 42 into the bore 32 which is connected to the brake cylinder passageway 38 when the cylinder seat 34 and screw seat 36 are spaced apart.

At the exterior end of the bleed screw, a tapered tip 46 is formed with a central exterior opening 48 at the tip forming the end of the passageway 40. In addition, a rearward facing shoulder 52 is formed at the rear end of the tip. Spaced from the shoulder 52 and formed on the exterior surface of the bleed screw is a nut section 54 which, as illustrated in FIG. 1, is of hexagonal configuration. Normally, the nut 54 is grasped with a tool, and when counterclockwise rotational movement is applied to the nut 54, the bleed screw moves outwardly from the brake cylinder 14, and the cylinder seat 34 and the screw seat 36 are separated from each other, as illustrated in FIG. 3, enabling fluid to pass into the bore 32.

The front end of the tool 12 contains a rearwardly extending socket bore 56 which extends from the front edge 58'of the tool rrearwardly to a forward facing shoulder 62 and is in a form of a socket which mates with the hexagonally-shaped nut section 54. A reduced diameter intermediate bore 64 extends rearwardly from the forward facing shoulder 62, the bore 64 being aligned with the socket bore 56. The bore 64 terminates at a forward facing shoulder 66 and a reduced rear bore 68 forms a continuation of the bore 64 rearwardly from the shoulder 66.

A resilient seal 72 is made of rubber and contains a passageway 74 which defines a right circular cylinder. The passageway is aligned with the axis of the bores 56 and 64 and extends from a first end which is defined by a shoulder 76 positioned in the bore 64 to a frustoconical sealing surface 77 which flares radially outwardly and terminates at a second end 78 positioned in the bore 56. The outer surface 79 of the seal 72 tapers from the second end 78 to a reduced width section at the shoulder 76.

A cylindrical tube 82 is positioned in the passageway 74 and extends from the junction of the sealing surface 77 and the passageway 74 into the reduced rear bore 68. The outer diameter of the tube 82 is approximately equal to the diameter of the reduced rear bore 68 and the passageway 74 so that a tight fit is formed therebetween. A spring 84 surrounds the tube 82. The spring is tapered so that s first end 86 is of approximately equal diameter to that of the outer diameter of the tube 82 at which point the spring abuts the shoulder 76 of the seal 72 and is secured to the tube 82. The spring then flares outwardly to a second end 88 which abuts the forward facing shoulder 66 of the tool.

As illustrated in FIG. 3, when the tool is positioned so that the socket bore 56 of the tool surrounds the nut 54, the sealing surface 77 of the rubber seal abuts the tapered tip 46 of the bleed screw. As the tool is positioned over the bleed screw, the spring 84 is compressed and a tight seal is formed between the rubber seal 72 at the sealing surface 77 and the tip 46. Thus, when the tool is rotated in a counterclockwise direction, loosening the bleed screw, fluidwhich passes from the brake cylinder through the passageway of the bleed screw will enter the passageway formed by the plastic cylindrical tube 82 and leakage will be prevented by means of the tight seal formed between the rubber seal 72 and the bleed screw. Simultaneously, it should be noted that a secondary seal is formed as the outer surface of the seal 72 is forced against the shoulder 62. Fluid will continue to pass from the cylindrical plastic tube 82 into the reduced rear bore 68 of the tool.

The reduced rear bore 68 follows the curvature of the tool 12 and terminates at an opening 92 of the tool. The rear end of the tool contains a reduced outer cylindrical diameter portion 96 which extends rearwardly until reaching a forward facing shoulder 98. Then a sleeve member 102 is formed on the shoulder with the forward facing surface 104 of the shoulder being in the form of a curved groove 105 which flares outwardly therefrom by means of a flared portion 106 and tapers to the outer diameter of the tool. Fluid in the bore 68 is coupled by means of the adaptor 18 into the reservoir 16. A cylindrical sleeve 114 of plastic tubing surrounds the reduced cylindrical portion 96 of the tool and abuts the rearward facing shoulder 98. A plurality of spring fingers 116 is formed on the outer surface of the sleeve 1l4 and extend froma base strip 118 secured to the outer surface of the tube. The spring fingers 1 l6 terminate in curved rolls 122. The diameter defined by the inner edges of the rools 122 is less than that of the periphery of the shoulder 98 and the rolls snap into the curved groove 105 securing the adaptor 18 to the rear end of the tool. The fluid can thus pass into the reservoir 16 through the sleeve 114 whose end surrounds the opening 92 of the tool.

A set of tools can be provided,'each with different size socket bores 56, with a rear end of each tool being of the same size so that a single adaptor 18 could be used with all tools of the set.

I claim:

1. A bleeding tool for a hydraulic brake cylinder having an externally disposed bleeding member comprising:

a tool having a generally hollow interior defining a passageway for fluid therethrough and having a front end having means formed thereon for loosening said bleeding member, enabling fluid to pass from said cylinder through said passageway;

a resilient member positioned in said tool hollow interior adjacent the front end thereof and having a bore surface therethrough defining a continuation of said tool passageway;

a tubular member interconnecting said bore surface of said resilient member with said tool passageway; and v spring biasing means positioning said resilient member adjacent said bleeding member for enabling said resilient member to provide a seal between said tool and said bleeding member and enabling fluid to pass directly from said bleeding member to said passageway without leakage.

2. A bleeding tool in accordance with claim 1 wherein the front end of said tool forms a socket for loosening said bleeding member and thereby enabling fluid to pass from said cylinder.

3. A bleeding tool in accordance with claim 1 wherein said resilient member has a tapered front end which fits securely against an opening in said bleeding member.

4. A bleeding tool in accordance with claim 3 wherein the front end of said resilient member bore is flared outwardly.

5. A bleeding tool in accordance with claim 1 wherein said tool passageway contains a forward facing shoulder, said spring biasing means being formed of a spring member, one end of which abuts said shoulder compressing said spring when said resilient member is positioned adjacent said bleeding member.

6. A bleeding tool in accordance with claim 5 wherein said tubular member comprises a plastic stem, the front end of said spring member surrounding said stem adjacent the rear end of said resilient member, said spring member retaining said stern in a predetermined position. 7

7. A bleeding tool in accordance with claim 5 wherein the outer surface of said resilient member ior of said tool. 

1. A bleeding tool for a hydraulic brake cylinder having an externally disposed bleeding member comprising: a tool having a generally hollow interior defining a passageway for fluid therethrough and having a front end having means formed thereon for loosening said bleeding member, enabling fluid to pass from said cylinder through said passageway; a resilient member positioned in said tool hollow interior adjacent the front end thereof and having a bore surface therethrough defining a continuation of said tool passageway; a tubular member interconnecting said bore surface of said resilient member with said tool passageway; and spring biasing means positioning said resilient member adjacent said bleeding member for enabling said resilient member to provide a seal between said tool and said bleeding member and enabling fluid to pass directly from said bleeding member to said passageway without leakage.
 2. A bleeding tool in accordance with claim 1 wherein the front end of said tool forms a socket for loosening said bleeding member and thereby enabling fluid to pass from said cylinder.
 3. A bleeding tool in accordance with claim 1 wherein said resilient member has a tapered front end which fits securely against an opening in said bleeding member.
 4. A bleeding tool in accordance with claim 3 wherein the front end of said resilient member bore is flared outwardly.
 5. A bleeding tool in accordance with claim 1 wherein said tool passageway contains a forward facing shoulder, said spring biasing means being formed of a spring member, one end of which abuts said shoulder compressing said spring when said resilient member is positioned adjacent said bleeding member.
 6. A bleeding tool in accordance with claim 5 wherein said tubular member comprises a plastic stem, the front end of said spring member surrounding said stem adjacent the rear end of said resilient member, said spring member retaining said stem in a predetermined position.
 7. A bleeding tool in accordance with claim 5 wherein the outer surface of said resilient member forms a secondary seal with a bore formed in the interior of said tool. 